随机噪声SAR的相干斑分析

Analysis of Speckle in Random Noise SAR

针对不同信号对相干斑的影响,探讨了随机噪声(RN)SAR的相干斑.由于随机噪声信号的非周期性,从物理角度解释了随机噪声SAR的相干斑弱于通常的线性调频信号SAR的相干斑,然后利用拖尾Rayleigh分布,采用标准差和等效视数(ENL)指标对两幅SAR幅度图像的相干斑进行了评价.通过对同一场景的随机噪声SAR幅度图像和线性调频SAR幅度图像相干斑进行仿真分析,结果表明随机噪声SAR的相干斑弱于线性调频SAR的相干斑.

Aimed at the impacts of various signals on speckles, the speckles of random noise SAR are studied in this paper. In view of non-periodicity of random noise signals, it is cleared that the speckles of random noise SAR are less than those of the common linear FM signal SAR in terms of physics, and then, by taking advantages of tailing Rayleigh distribution, the speckles of two SAR amplitude images are assessed by means of standard deviation and ENL indexes, and finally, the speckle analysis of random noise SAR amplitude image and linear FM SAR amplitude image in the same scene, by using the test data. Experimental results show that the speckles of random noise SAR are really weak, compared with those of linear FM SAR.